Marriage in India is a union between two families rather than two individuals and the procedure tends to follow a strict pattern.

Love stories highlight durability of class and religious divides. Amir Mirza first noticed his future wife, Swati, when she arrived at the home of a physics tutor they both went to.

Four years on, he still recalls it was her "really green" eyes that made a lasting impression. In between classes the teenagers would chat about grades, exams and the difficulties of getting into good colleges. Friendship blossomed in the dusty streets of the Indian town of Kosamba, in Gujarat. Soon Amir and Swati were falling in love.

Their conversations turned to marriage and kids. In many countries few people would consider that unusual. But in small town India, Amir and Swati had dared to break two social taboos, with disastrous results. Not only had they chosen each other without parental consent but Amir, a Muslim, wanted to marry a Hindu.

What followed was a cautionary tale about love and marriage in a country where economic progress has brought only superficial changes to a conservative society. Marriages are arranged in the interests of the family or community - choosing a partner is too important a step to be left to chance.

Towns in Gujarat are distinguished by a religious segregation. In Kosamba, Hindus and Muslims live on opposite sides of the main road and rarely mix more deeply than meeting in markets and schools.

"My parents were against [the marriage]. Her parents had problems. Our friends thought it was a bad idea. At that time we only had ourselves," says Amir. To be together they eloped to the southern city of Bangalore. "We had to get away. I took out all my savings, about 8 lakhs, and we got married on June 21, 2006. The happiest day for us."

In an attempt to win over their parents, the newlyweds returned to Gujarat a few months later, only for a now-pregnant Swati to be kidnapped by her family.

"They invited us over for lunch and then grabbed me from the car with the help of some of their friends," she says, blinking away the tears. Drugged and locked up in her brother's house, the 19-year-old says she was forced to sign papers claiming her husband had assaulted her. Later she was taken to a hospital where she was anaesthetised and an abortion of her 63-day-old foetus induced.

"I lay down with terrible stomach pains. There was blood and I blacked out. I do not remember anything but know I lost our child," says Swati, who escaped after two weeks' imprisonment. She says her family disowned her after she refused to renounce Amir. Swati says her family's actions mean she will take a new name, Mariam, and adopt "as much Islam" as she can.

The couple are now in hiding but they agreed to be interviewed at the Mirza family home. Amir says his parents have reluctantly agreed to their marriage.

"No one is happy," he says. Across the road in Kosamba's Hindu suburbs is the home of one of the men accused by the young lovers of kidnapping Swati. Mohan Chowksi, a local jeweller, admits comforting Swati's family, but denies any crime.

"Under our customs Hindus should not marry Muslims. But I did not take the girl," he says. "The Muslims have brainwashed her. She is not madly in love - just mad."

Despite modern India's new malls and shiny office blocks, traditional values are deeply entrenched in a society where family, caste and religious obligations persist. Nowhere is this more obvious than in affairs of the heart.

An opinion poll of 15,000 people, carried out in January by Delhi's Centre for the Study of Developing Societies, found that 70% of Indians thought parents should have the final say in marriage. Less than a third of young people said it was OK to "date".

Some couples have defied their parents and settled down despite the disapproval - but almost all come from the upper and middle classes. Josephine Joseph, a Christian, had to wait six years to marry her Hindu husband, B P Thanmaya.

Both come from highly educated, liberal families. Josephine, 30, says she had had two close relationships before; but her family expected her to marry a Christian from her home state of Kerala.

"My mum kept saying my dad was unwell, and could not break the news to him. Really she did not know how he would react. There was a lot of worry about what [Christians] would say."

"My father-in-law wanted me to convert [to Hinduism]. I refused. We wanted to get married to each other. It took years but in the end everyone had to accept it. It was a church wedding one day and a Hindu one the next."

The most vehement opposition in India is to inter-caste marriages. In the survey, three-quarters of Indians said it was wrong to marry a person from a different caste. India remains a stratified society and the caste system relies on marriages being arranged to preserve bloodlines and lineage. A romance across the caste divide is often fatal.

In the back streets of a poor housing colony in east Delhi, a father weeps for his dead son. Chander Bhan Kumar, who comes from a dalit, or untouchable, community, says his eldest boy, Kishan, was killed because he dared to marry an upper-caste girl, Laxmi, in 2005.

Her family abducted her 10 days after the ceremony, and the two were kept apart. Mr Kumar says Kishan, 26, refused to give up hope. But last November he was shot dead while sitting on his motorbike in traffic. Five men, including Laxmi's two brothers and father, have been arrested.

The police said the brothers killed Kishan to "avenge humiliation". "Kishan loved that girl, but the family could not bear marrying into our family," said Mr Kumar.

"It was shame for them. But my son had his heart broken and then was killed. All because of love. Even today, being low caste can lead to death." In many aspects, Indian marriages appear more of a commercial transaction than a romantic expression. Matrimonial adverts carried on the internet and in newspapers generally list the caste, age and education of prospective brides. Women are marketed as "fair'' or with a "wheatish complexion".

Dowries are widely negotiated, despite being illegal. Dipankar Gupta, professor of sociology at Delhi's Jawaharlal Nehru University, says there is "very little real freedom to choose one's own way in life.

"India is not a liberal society in that sense. Marriage is a very obvious example where even today most young people cannot easily choose their own partner."

Backstory The triumph of romantic love may be celebrated in Bollywood but it is estimated that 95% of Indians have arranged marriages. Marriage in India is a union between two families rather than two individuals. The procedure tends to follow a strict pattern. A girl's parents put the word about that they are looking for an "alliance".

India's scores of marriage websites are well subscribed to and pages buzz with pictures and CVs. Once a suitable boy has been found, families exchange summaries that list a person's attributes. Horoscopes are also consulted. There follows tea so that prospective groom and bride can check each other out.

If they like each other, more discreet meetings can be arranged. Once a proposal is accepted, it is not unusual for families to check that the groom was honest about his job and income.

Dowries, under the law, can be given but not asked for. In reality there is a negotiation. Divorce rates are rising, but the law is biased against women - who unlike their counterparts in the west are only entitled to maintenance and alimony, not a chunk of wealth.